Autoprotective x-ray tube



Aug. 13, 1935. J. F. LEE

AUTOPROTECTIVE X-RAY TUBE Filed July 14, 1934 INVENTOR' MW/(5f @w'wzh TTORNEY Patented Aug. 13, 1935 AUTOPROTECTIVE X-RAY TUBE James F. Lee, Palo Alto, Calif. Application July 14, 1934, Serial No. 735,127

4 Claims.

This invention relates to X-ray tubes of the autoprotective type wherein the tube proper is enclosed during use in a casing of material which is opaque both to X-rays and light rays-the purpose of the casing being to afford protection to the operator against exposure to X-rays.

With the ordinary autoprotective tube the operator cannot see the target during operation; and generally it is not necessary for him to see it because he operates according to a rating chart provided by the tube manufacturer and, when so operated, the tube is in no danger of injury.

Manufacturers" ratings always allow a margin of safety and can be exceeded to a certain extent without too much danger to the tube if the operator is sufficiently skilled and able to determine from visual observation of the hot target when he has reached the limit beyond which he cannotsafely go. And there are cases'occurring in practice where it is highly desirable to work the tubes to the limit, even at the risk of destruction.

The object'of. the present invention is to make it possible forthe operator of an autoprotective tube to visually observe the target during operation without danger to himself and to incorporate the means to that end into the tube structure; or, more specifically, into the structure of the autoprotective casing which encloses the tube proper.

In pursuance of the foregoing object, my m vention contemplates the incorporation into an X-ray tube structure, and especially an autoprotective tube structure, of a periscope capable of transmitting light but opaque to X-rays andso arranged that the operator of the tube is enabled to observe the target during operation without danger to himself.

Inthe accompanying drawing:

Fig. l is an elevational view of an autoprotective X-ray tube provided with a periscope-the mid-portion being shown in section;

' Fig. 2 is a cross-sectional View taken along the line 22 of Fig. l;

The structure of Fig.1 comprises an X-ray tube proper designated as a whole by reference numeral I, a radiator 2 of conventional design, and an autoprotective casing 3 which encloses the tube proper and is provided with a periscope 4 so situated as to render the face of the tube target visible tothe operator by reflection without The particular structural design of the autoprotective casing as a whole is not important so.

far as the present invention is concerned, but it consists, in the arrangement illustrated, of a pair of tubular leaded bakelite end pieces ill and II, a brass mid-portion l2, a sheet lead tubular interlining l3 and a glass inner tube I4. The casing is constructed with a suitable window for the emergence of X-rays and this is indicated in Fig.

2 by reference numeral l5.

The periscope 4 comprises two co-related light reflecting mirrors I6 and H which serve to reflect an image of the focal spot as indicated by the dot and dash line 18. The exterior of the periscope is rectangular in form and it may be made of sheet brass lined with sheet lead. The important thing is that it be so designed and constructed that harmful X-rays cannot emerge and injure the operator. i

The periscope may conveniently be placed at an angle of about 90 degrees to the X-ray winnot critical.

What is claimed is: r 1. The combination with an X-ray tube of an autoprotective casing thereforhaving a periscope vdow, as illustrated, but, obviously, that angle is g attached thereto, said periscope being transparent to light and opaque to X-rays.

2. The combination with an X-ray tube of an autoprotective casing therefor having a periscope attached thereto, said periscope comprising .a plurality of co-related mirrors so situated as to permit observation of an image of the focal spot 1 I through i without permitting passage of X-rays the periscope.

3. The combination with an X-ray tube of an autoprotective-casing therefor having a periscope attached thereto, said periscope comprising a housing which is opaque to X-rays and a pair of co-related. mirrors within said housing, said mirrors being so situated as to permit observation of an image of the focal spot without per-' mitting passage of X-rays through the periscope.

4. The combination with an X-ray tube including an X-ray emissive target, of an autoprotective casing therefor having 7 incorporated therein light reflecting means opaque to X-rays, said means being operable to receive light rays propagated, from the target and to retransmitthe same by reflection to theexterior of the tube whereby an image of the focal spot is rendered,

visible to the operator without exposing the op.- erator to X-rays.

JAMES F. 

